The present invention relates to novel mixtures having growth-regulating properties and more specifically relates to a novel growth regulating mixture of quaternary ammonium salts with growth regulating active ingredients in a suitable solvent. The invention further relates to methods for regulating plant growth.
Plant growth regulators (xe2x80x9cPlant Growth Regulatorsxe2x80x9d) serve many useful purposes in the areas of crop cultivation, agriculture and gardening. For instance, a particular concern in cultivating such crops as grain, corn, sunflowers and soybeans, is the problem of lodging of the plants due to unfavorable weather conditions prior to harvest. Inhibiting the longitudinal growth of the plants results in a thicker, stronger stem, thereby reducing the risk of lodging. Also, by inhibiting longitudinal growth of cotton crops, the course of maturation can be controlled in order to permit completely mechanized harvesting.
Growth regulation of fruit trees can result in reduced trimming costs, while also enabling the grower to restrict annual fluctuations in fruit tree yield.
Some Plant Growth Regulators can also be used to control the susceptibility of crops to adverse weather conditions by improving frost resistance. This is particularly useful in winter grain. Excess longitudinal growth and the development of overly lush leaves results in a more frost-vulnerable plant. It is also desirable to inhibit growth even during favorable growing conditions for example after sowing and before winter frosts begin. This results in a plant that is less vulnerable to frost. In addition to increased frost resistance, the relatively small leaf and plant mass become less susceptible to diseases such as fungus. Regulating growth of crop plants also enables many crop plants to be planted closer together resulting in a higher yield from a given area.
Quaternary ammonium salts, such as mepiquat chloride and chloromequat chloride, whose formulas are depicted below, are known Plant Growth Regulators. 
These compounds are commercially available in aqueous concentrates or in tablet or granule form (e.g. PIX(copyright) plant growth regulator, BASF Corporation). These compounds can be made by methods known in the art, such as, by converting secondary or tertiary amines with methyl halides. A method for water-free preparation of mepiquat chloride, which can be used as a solid charge stock in formulations, is described in European Patent Application, Publication No. 0 573 177 A2, incorporated herein by reference.
Other known active ingredients having growth regulating properties are described in European Patent Application, Publication No. 0 243 834 A2 and include the following formula: 
In this formula, the radicals have the following meanings: R1 and R2 independently of one another may be hydrogen, C1-C6 alkyl, C1-C6 halogen alkyl, C1-C4 alkoxy-C1-C6 alkyl, C3-C6 alkenyl and phenyl, which may be unsubstituted or may carry one or independently of one another two or three of the following groupsxe2x80x94nitro, chloro, fluoro, C1-C3 alkyl, C1-C3 haloalkyl, and methylene dioxy; or R1 and R2 together with the carbon atom to which they are bonded form a 5- to 7- member ring, which in turn may carry one or independently of one another two C1 -C3 alkyl groups; R3 may be hydrogen, a cation suitable for agriculture, C1-C8 alkyl, C3-C7 cycloalkyl, C1-C4 alkyloxy- C1-C6 alkyl, or a CH2-C(O)-OR4 group, wherein R4 stands for C1-C8 alkyl, C3-C7 cycloalkyl, C1-C4 alkyloxy-C1-C6 alkyl, hydrogen or a cation suitable for agriculture.
Other active ingredients that have been described as possessing growth regulating properties include acylcyclohexadiones for example those described in U.S. Pat. No. 4,560,403, incorporated herein by reference, as represented by the formula: 
wherein R represents a hydrogen atom or an alkyl group, an alkylthioalkyl group or an unsubstituted or substituted phenyl group; and R1 represents an alkyl group, an unsubstituted or substituted benzyl group, a phenethyl group, a phenoxymethyl group, a 2-thienylmethyl group, an alkoxymethyl group or an alkylthiomethyl group, or a salt of said cyclohexane compound.
A specific compound for use as a growth regulating compound is prohexadione represented by the formula: 
As used herein, prohexadione includes the compound (IUPAC name) 3,5-dioxo-4-propionylcyclohexanecarboxylic acid (or 3,5-dioxo-4-(1-oxopropyl)cyclohexanecarboxylic acid (C.A. name)) and also 3-hydroxy-4-prionyl-5-oxo-3-cyclohexene carboxylic acid and its pharmacological effective salts for example a chloride, sulfate, metrab, acetate, carbonate, hydride, hydroxide, sodium, potassium, calcium, magnesium, barium, aluminum, nickel, copper, manganese, cobalt zinc, iron or silver.
Other acylcyclohexadione compounds having growth regulating properties are described in U.S. Pat. No. 4,693,745, incorporated herein by reference, and are represented by the formula: 
wherein
A is an xe2x80x94OR2 or xe2x80x94NR3R4 radical,
R is C3-C6 cycloalkyl,
R2 R3 and R4 are each independently hydrogen, C1-C6alkyl, C1-C6haloalkyl, C2-C10alkoxyalkyl, C2-C10alkylthioalkyl, C3-C6alkenyl, which is unsubstituted or substituted by halogen, C1-C4alkoxy or C1-C4alkylthio; C3-C6alkynyl; phenyl or C1-C6aralkyl, wherein the phenyl nucleus is unsubstituted or substituted by halogen, C1-C4alkyl, C1-C4alkoxy,
C1-C4haloalkyl, nitro or cyano; one of R3 and R4 is methoxy; or
R3 and R4, together with the nitrogen atom to which they are attached, form a 5- or 6- membered heterocyclic ring system which may contain an additional oxygen or sulfur atom in the ring; and the metal or ammonium salts thereof.
Specific compounds of the immediately above noted formula include trinexapac (IUPAC name 4-cyclopropyl(hydroxy)methylene-3,5-dioxyocyclohexanecarboxylic acid) and preferably its ethyl ester, trinexapac-ethyl (IUPAC name, ethyl 4-cyclopropyl(hydroxy)methylene -3,5-dioxocyclohexanecarboxylate; CA name, ethyl 4-(cyclopropylhydroxymethylene) -3,5-dioxyocyclohexanecarbocylate) represented by the formula: 
Mixtures of active ingredients with quaternary ammonium salts, such as those of formulations I(a) and I(b)1 are discussed in European Patent Application, Publication No. 0 434 613 A2. Although there mixture provide useful and beneficial properties, superior stability properties are sought for mixtures of active ingredients.
It is therefore an object of the present invention to create a formulation having growth regulating properties by combining the salt-like active ingredients of formulas I(a) and/or I(b), in a solution while simultaneously maintaining stability of the active ingredients. Another object of the present invention is to obtain growth-regulating properties by combining ingredients of formulas I(a) and/or I(b), with active ingredients of formulas III or with a acylcyclohexadione, and maintain the stability of the active ingredients.
The present invention provides formulations in which salt-like active ingredients, such as the quaternary ammonium salts of formulas I(a) and I(b), are dissolved in suitable organic solvents, in which other active ingredients with growth regulating properties, such as those of formula III, IV or V, can also be added while maintaining adequate stability of the active ingredients. While it is known that salt-like active ingredients such as quaternary ammonium salts are soluble in water, due to their polar, salt-like and inorganic characteristics, such aqueous solutions may cause degradation of other active ingredients used in growth regulating mixtures.
It has been found, surprisingly, that the salt-like formulations I(a) and I(b) are suitably soluble in organic solvents having either of the following two formulas which are referred to herein as formulas II(a) and II(b) respectively: 
wherein
xe2x80x9cRxe2x80x9d is Hydrogen or a C1-C18 alkyl,
xe2x80x9cnxe2x80x9d is 0, 1, 2 or 3,
xe2x80x9cAxe2x80x9d is a C1-C6 alkene or a C1-C6 oxyalkylene,
xe2x80x9cmxe2x80x9d is 1, 2, 3, 4 or 5, and
xe2x80x9cBxe2x80x9d is a straight-chain or branched C2-C8 alkylene.
While these solvents provide adequate solubility of salt-like active ingredients of formulas I(a) and/or I(b), they also are good solvents for active ingredients of formulas III, IV and V. Moreover, use of these solvents has been found to result in very good stability of active ingredients in solution. Particular advantage may be found by combining the salt-like active ingredients of formulas I(a) and or I(b) in combination with compounds of formulas III, IV and/or V. Growth regulating properties are attained and the mixtures adequately sustain the stability of the active ingredients. These formulations are preferably provided in the substantial absence of water.
Preferred embodiments of the invention include mixtures comprising quaternary ammonium salts of formulations I(a) and/or I(b) in the amount from 1-50% by weight, preferably 2-30% by weight, and in particular 3-25% by weight of the mixture.
The solvents of formula II(a) may comprise derivatives of aromatic alcohols or ethers. Aromatic alcohols are preferred in which the OH group is bonded to the aromatic ring via an alkylene group having from 1 to 4 Carbon atoms or an oxyalkylene group having from 2 to 6 Carbon atoms. In some cases, benzyl alcohol, ethylene glycol monophenylether, propylene glycol monophenylether, butylene glycol monophenylether and the derivatives thereof, substituted in the aromatic ring with 1 to 3 C1-C3 alkyl groups, have been said to be particularly advantageous.
The solvents of formula II(b) may comprise linear or branched diols with a C2-C8 alkylene chain. The two hydroxy groups can be located either at the end or inside the chain. Preferred representatives of the solvents of formula II(b) are propylene glycol and butylene glycol. By comparison, the stability of the active ingredients in those solvents is somewhat better than in ethylene glycol.
The amount of solvents of formulas II(a) and/or II(b) in the formulation of the invention is preferably provided in the range of from 20-99% by weight, preferably from 35-98% by weight, and particularly from 50-96% by weight, with reference to the total weight of the formulation.
The formulation can also have from 0-60% by weight, preferably 1-50% by weight and particularly 2-35% by weight of further active ingredients. Active ingredients such as those having formulas III, IV, and or V III(b) are known. For example, compounds of formula III are described generally in PCT Application WO 96/00005. Their effect in reducing the endogenous ethylene content in higher-order plants is described for instance in German Patent Disclosures DE 36 13 649, DE 41 06 509 and U.S. Pat. No. 4,744,811..
An active ingredient for use in the present invention is represented by Formula IV(a) an example of which a prohexandione.
One preferred active ingredient is represented Formula V(a) and a preferred example of which is trinexapac-ethyl.
With reference to formula III, instead of the free acids their agricultural acids may also be present. In general the type of salt does not matter. Typically the salts of those bases that do not negatively affect the action of the compounds of formulas III, IV and V. As basic salts, those that are especially suitable are those of alkaline metals, preferably the salts of sodium and potassium, the salts of alkaline earth metals, preferably calcium, magnesium, copper, zinc and iron salts, and the ammonium salts, which can have from 1 to 3 C-C4 alkyl substitutes and/or a phenyl or benzyl substitute, preferably diisopropyl ammonium, tetramethyl ammonium, tetrabutyl ammonium, trimethylbenzyl ammonium, and trimethyl-(2-hydroxyethyl) ammonium salts, the phosphonium salts, the sulfonium salts, preferably tri-(C1-C4-)alkyl sulfonium salts, and the sulfoxonium salts, preferably tri-(C1-C4-) alkyl sulfoxonium salts.
Preferred active ingredients having the formula set forth as formula III are compounds having the following combinations of radicals:
(1) the R1 and R2 radicals are C1-C6 alkyls, such as methyl, ethyl, propyl, or the R1 and R2 radicals, together with the Carbon to which they are bonded form a 5- to 7-member ring, such as cyclopentylidine or cyclohexylidine;
(2) the R3 radical is hydrogen, a C1-C6 alkyl group, or a CH2xe2x80x94C(O)OR4 group; and
(3) the R4 radical is hydrogen or a C1-C6 alkyl group.
Other preferred active ingredients of formulation III(a) are those listed below and designated as formulas III(a)-III(d): 
and the acids on which they are based and their alkali, alkaline earth or ammonium salts.
The mixtures of the present invention can also have, as components up to 30 percent by weight and preferably up to 20 percent by weight, further formulation adjuvants, of the kind known to one skilled in the art such as, for example, the adjuvants named in European Patent Disclosure EP A 434 613 and incorporated herein by reference.
When surface-active substances are used as further formulation adjuvants, the substances that can be considered are the alkali, alkaline earth and ammonium salts of aromatic sulfonic acids, such as lignin-, phenol-, naphthalene-, and dibutylnaphthalenesulfonic acid, as well as those of fatty acids, alkyl and alkylaryl sulfonates, alkyllaurel ether and fatty alcohol sulfates, and salts of sulfated hexa-, hepta- and octadecanols or fatty alcohol glycol ethers, condensation products of sulfonated naphthalene and its derivatives with formaldehyde, condensation products of naphthalene or naphthalenesulfonic acids with phenol and formaldehyde, polyoxyethylene octyl phenol ether, ethoxylated isooctyl, octyl or nonylphenol, alkylphenol or tributylphenyl polyglycol ether, alkylaryl polyether alcohols, isotridecyl alcohol, fatty alcohol ethylene oxide condensates, ethoxylated castor oil, polyoxyethylene alkyl ether or polyoxypropylene, lauryl alcohol polyglycol ether acetate, sorbitol ester, lignin sulfite waste liquors, or methylcellulose.
The formulations according to the invention can be prepared in a manner known by those ordinarily skilled in the art such as by adding compounds of formulas I(a) and/or I(b), and active ingredients of formulas III, IV and/or V and other formulation adjuvants into the organic solvents of formulas II(a) and/or II(b), while stirring and, optionally, while heating.
The preferred use of the formulations according to the invention is to treat plants at preemergence or at the postemergence stage with an effective amount of the formulation on the basis of active ingredients of formulas I(a) and/or I(b), or the mixtures of these active ingredients of formulas I(a) and/or I(b) with ingredients of formulas III, IV and/or V. Seed dressing is also another possible use of the present invention.
Depending on the season, the target crops, and the stage-of growth, the quantities of mixture applied may range from 0.0001 to 1.0, preferably 0.001 to 0.5, and especially 0.001 to 0.1 kg/ai/ha.
The mixtures may effect practically all development stages of a plant in various ways and are therefore used as growth regulators. The versatility of action depends on the following factors:
(a) the species and variety of plant;
(b) the timing of the application, with respect to the development stage of the plant and the season of the year;
(c) the application site and application method (such as, seed dressing, soil treatment, leaf application or in tree trunk injection);
(d) climatic factors, such as temperature, amount of precipitation, and also length of day and intensity of light;
(e) soil property, including fertilization,
(f) the concentrations used of the active substances I(a) and/or I(b) and III(a) and/or III(b).
From among the numerous uses of the mixtures of the present invention, and agents containing them, in crop cultivation, in agriculture and in gardening, several are mentioned below.
With these mixtures and agents, the vegetative growth of the plants can be sharply inhibited, which is expressed as a reduction in longitudinal growth. Hence, the treated plants exhibit a dwarfed growth and a darker leaf coloration.
Furthermore, the mixtures according to the invention can cause a reduction in endogenous ethylene formation in the treated plants. This leads to
a retardation of senescence phenomena and can thus prolong the life of cut flowers and lengthen the assimilation phase of crop plants and bring about increased harvest yields;
a reduction or at least temporary delay in dropping of leaves, blossoms and fruit;
an improvement in the formation of root nodules in leguminous plants and hence more-intensive assimilation of nitrogen from the air;
a reduced sensitivity to stress situations (such as lack of water, low temperatures, mechanical strain, attach by harmful fungi or insects).
Also, with the mixtures of the present invention, increased yields of both plant parts and plant ingredient substances can be attained. It is thus possible for instance to induce the growth of greater amounts of buds, blossoms, leaves, fruits, seed grains, roots and nodes, to increase the sugar content in sugar beets, cane sugar and citrus fruits, to increase the protein content of grain or soybeans, or to increase the yield of cellulose fibers from cotton.
The mixtures of the present invention can also be used to bring about increases in yields by intervening in plant metabolism or by promoting or inhibiting vegetative and/or generative growth.
Also, with these mixtures, not only can the stages of development be shortened or lengthened, but the maturation of harvested plant parts, before or after the harvest, can be accelerated or delayed. Thus, for instance, a more-concentrated timing of cotton bole maturation can result in a greater ease of harvesting for the grower.
The consumption of water by plants can also be reduced by practicing the invention herein described. This is especially important for agricultural areas that require artificial irrigation at high expense, such as in arid or semiarid regions. The intensity of irrigation can be reduced by using the agents according to the invention, making farming less expensive. Under the influence of the agents:
the width to which the stomata open is reduced;
a thicker epidermis and cuticle are formed;
root proliferation in the soil is improved; and
the microclimate in the planted fields is favorably affected by more-compact growth.
The mixtures can be supplied to the crop plants both from seed (as a seed dressing agent) or via the soil, that is, through the roots, and preferably by spraying the shoots. Given the versatility of application methods, the mixtures can be used in a great number of crop plants.
In preparing the mixtures, one preferably uses the pure active ingredients of formulas I(a) and/or I(b) and of formulas III, IV and/or V, to which other active ingredients can be added, such as active ingredients that regulate plant growth, herbicidal active ingredients, and active ingredients that protect against harmful fungi or animal pests, or fertilizers.